1. Field of the Invention
The present invention relates to compounds and methods for treating a disorder and/or condition having a IκB/NFκB-mediated chronic inflammatory response (e.g. cystic fibrosis).
2. Background
The IκB/NFκB-mediated chronic inflammatory response is a known component of a variety of diseases and disorders, including, for example, cystic fibrosis, diabetes, Parkinson's Disease, Alzheimer's Disease and others. NFκB is a transcription factor which mediates extracellular signals responsible for induction of genes involved in pro-inflammatory responses (see U.S. Pat. No. 5,804,374), including the production of various cytokines such as interleukin-8 (IL-8). NFκB is anchored in the cytoplasm of most non-stimulated cells by a non-covalent interaction with one of several inhibitory proteins known as IκBs (see May & Ghosh, (1997) Semin. Cancer. Biol. 8, 63-73; May & Ghosh, (1998) Immunol. Today 19, 80-88; Ghosh et al., (1998) Annu. Rev. Immunol. 16, 225-260). Cellular stimuli associated with pro-inflammatory responses in turn activate NFκB through the phosphorylation of the IκBs. Phosphorylation targets IκBs for ubiquitination and degradation by the proteasome. The degradation and subsequent dissociation of IκBs from NFκB reveals the nuclear localization signal on NFκB, resulting in nuclear translocation of active NFκB, leading to up-regulation of genes responsive to NFκB, which include various cytokine such as IL8 associated with a variety of disorders (May & Ghosh, (1997) Semin. Cancer. Biol. 8, 63-73; May & Ghosh, (1998) Immunol. Today 19, 80-88; Ghosh et al., (1998) Annu. Rev. Immunol. 16, 225-260; Siebenlist et al., (1994) Annu. Rev. Cell Biol. 12, 405-455).
One important disease which involves in part an NFκB mediated pro-inflammatory response is cystic fibrosis. This disease is the most common lethal recessive genetic disease in the United States (Di Sant' Agrese et al., Am J. Med. (1979) 66:121-132). In the United States, the disease occurs once in every 1500 to 2000 Caucasian live births and once in every 17,000 Afro-American live births (Steinbert et al., Am. J. Human Genet. (1969) 12:416-424; ICramm et al., Am. J. Public Health (1962) 52:2041-2051; Merritt, et al., J. Lab. Clin. Med. (1962) 60:990-999; and Shultz et al., Am. J. Public Health (1966) 56:1461-1469). Despite current standard therapy, the median age of survival is only 26 years, wherein about 50% of individuals with cystic fibrosis die before reaching the age of 21 years.
The major cause of mortality and morbidity in patients with cystic fibrosis is progressive pulmonary disease, which is responsible for about 95% of the mortality (Stern et al., J. Pediatrics (1976) 89:406-411). In cystic fibrosis individuals, lung disease is not present at birth but typically develops later during childhood or adolescence (Sturgess et al., Am. J. Pathol. (1992); 106:303-311).
While great progress has been made, much still is unknown about the pathogenesis of cystic fibrosis. In the early stages of disease, inflammation of small airway leads to the formation of lesions. This early inflammation is generally thought to be linked to bacterial infection as cystic fibrosis patients have distinctive respiratory flora (Mearns et al., Arch. Dis. Child (1972) 47:902-907). In particular, Staphylococcus aureus is generally the dominant organism early in the course of cystic fibrosis disease, which is supplanted later in disease progression by Pseudomonas aeruginosa, and in particular mucoid strains of P. aeruginosa (Tococca et al., Am. J. Dis. Child (1963) 106:315-325).
As infections and inflammation become established in airways of the cystic fibrosis patient, hypertrophy and hyperplasia of the mucous-secreting apparatus develops, ciliated cells are replaced by goblet cells, and squamous metaplasia becomes pronounced. Beneath impacted mucous, denudation and ulceration of the mucosa may occur. Gradually, this destruction progresses up the respiratory tree to involve the larger airways. Structural damage to the bronchial wall occurs, and bronchiectasis develops. Bronchiectasis and mucopurulent plugging are present in most cystic fibrosis patients even at very early ages (Bedrossian et al, Human Pathol. (1976) 7:195-204.).
Several factors contribute to the progression of lung disease in cystic fibrosis patients. One of the most important factors, however, is the thick, viscous nature of airway mucous. Not only do thick secretions obstruct airways and contribute to reduced lung volumes and expiratory flows, but they also cause the inflammatory process to stand within the airways, thereby exposing the airway mucosa to a more abundant protease and oxidant rich environment than if the purulent respiratory secretions were easily expectorated. The enhanced viscoelastic properties of purulent secretions is due in part to the presence of highly polymerized, polyanionic deoxyribonucleic acid (DNA) from the nuclei of degenerating polymorphonuclear neutrophils (PMNs). Also, contributing to sputum tenacity is the presence of abundant cross-linked actin filaments from the cytosol of PMNs.
Upper airways of the nose and sinuses are also involved in cystic fibrosis. For example, most patients develop chronic sinusitis. Nasal polyps occur in 15-20% of patients and are common by the second decade of life. In addition, gastrointestinal problems are frequent in cystic fibrosis. Infants, in particular, may suffer meconium ileus. Further, exocrine pancreatic insufficiency, which produces symptoms of malabsorption, is present in the large majority of patients with cystic fibrosis. Males are almost uniformly infertile and fertility is decreased in females.
The protein product of the cystic fibrosis associated gene is called the cystic fibrosis transmembrane conductance regulator (CFTR) (Riordan, J. R. et al. (1989) Science 245:1066-1073). CFTR is a protein of approximately 1480 amino acids made up of two repeated elements, each comprising six transmembrane segments and a nucleotide binding domain. The two repeats are separated by a large, polar, so-called R-domain containing multiple potential phosphorylation sites. Based on its predicted domain structure, CFTR is a member of a class of related proteins which includes the multi-drug resistance (MDR) or P-glycoprotein, bovine adenyl cyclase, the yeast STE6 protein as well as several bacterial amino acid transport proteins (Riordan, J. R. et al. (1989) Science 245:1066-1073; Hyde. S. C. et al. (1990) Nature 346:362-365). Proteins in this group, characteristically, are involved in pumping molecules into or out of cells.
CNTR has been postulated to regulate the outward flow of anions from epithelial cells in response to phosphorylation by cyclic AMP-dependent protein kinase or protein kinase C (Riordan, J. R. et al. (1989) Science 245:1066-1073; Frizzell, R. A. et al. (1986) Science 233:558-560; Welsh, M. J. and Liedtke, C. M. (1986) Nature 322:467; Li, M. et al. (1988) Nature 331:358-360; Hwang, T-C. et al. (1989) Science 244:1351-1353).
Sequence analysis of the CFTR gene of cystic fibrosis chromosomes has revealed a variety of disease causing mutations (Cutting, G. R. et al. (1990) Nature 346:366-369; Dean, M. et al. (1990) Cell 61:863:870; and Kerem, B-S. et al. (1989) Science 245:1073-1080; Kerem, B-S et al. (1990) Proc. Natl. Acad. Sci. USA 87:8447-8451). Population studies have indicated that the most common cystic fibrosis mutation is a deletion of the 3 nucleotides that encode phenylalanine at position 508 of the CFTR amino acid sequence (ΔF508-CFTR), which is associated with approximately 70% of cystic fibrosis cases. This mutation results in the failure of an epithelial cell chloride channel to respond to cAMP (Frizzell R. A. et al. (1986) Science 233:558-560; Welsh, M. J. (1986). Science 232:1648-1650; Li, M. et al. (1988) Nature 331:358-360; Quinton, P. M. (1989) Clin. Chem. 35:726-730). In airway cells, this leads to an imbalance in ion and fluid transport. It is widely believed that this causes abnormal mucus secretion, disrupted luminal hydration, heightened immune response and ultimately results in pulmonary infection and epithelial cell damage described above.
To date, the primary objectives of treatment for cystic fibrosis have been to control infection, promote mucus clearance, and improve nutrition (Boat, T. F. et al. in The Metabolic Basis of Inherited Diseases (Scriver, C. R. et al. eds., McGraw-Hill, New York (1989)). Intensive antibiotic use and a program of postural drainage with chest percussion are the mainstays of therapy. However, as the disease progresses, frequent, hospitalizations are required. Nutritional regimens include pancreatic enzymes and fat-soluble vitamins. Bronchodilators are used at times. Corticosteroids have been used to reduce inflammation, but they may produce significant adverse effects and their benefits are not certain. In extreme cases, lung transplantation is sometimes attempted (Marshall, S. et al. (1990) Chest 98:1488).
Currently known approaches for dealing with cystic fibrosis generally include both therapies and/or treatments that are targeted towards ameliorating the symptoms of cystic fibrosis, e.g. pulmonary mucus therapies, and treatments that target the underlying genetics and/or pathophysiology of the disease, e.g. underlying immune response and genetics of the disease. In one exemplary approach, pharmacological treatments aimed at correcting the abnormalities in electrolyte transport associated with cystic fibrosis are being pursued. In another approach, “protein replacement” seeks to deliver functional, recombinant CFTR to cystic fibrosis mutant cells to directly augment the missing CFTR activity. Protein replacement therapy for cystic fibrosis could include a preparation of highly purified recombinant CFTR formulated in an appropriate carrier suitable for delivery to the airways by instillation or aerosol. Such replacement therapeutics have met with many difficulties, however, not the least of which includes the difficulty in purification of and handling of CFTR. Still in a further approach, gene therapy has been explored by which DNA encoding CFTR is transferred to CFTR defective cells (e.g. of the respiratory tract). However, methods to introduce DNA into cells are generally inefficient, unpredictable, and pose many health risks.
Cystic fibrosis, like many other disorders, is in part an inflammatory disease. Inflammation is defined as the reaction of vascularized living tissue to injury. As such, inflammation is a fundamental, stereotyped complex of cytologic and chemical reactions of affected blood vessels and adjacent tissues in response to an injury or abnormal stimulation caused by a physical, chemical or biological agent Inflammation usually leads to the accumulation of fluid and blood cells at the site of injury, and is usually a healing process. However, inflammation sometimes causes harm, usually through a dysfunction of the normal progress of inflammation. Inflammatory diseases are those pertaining to, characterized by, causing, resulting from, or becoming affected by inflammation. Examples of inflammatory diseases or disorders or those having an inflammatory component, besides cystic fibrosis include, without limitation, asthma, lung inflammation, chronic granulomatous diseases such as tuberculosis, leprosy, sarcoidosis, and silicosis, nephritis, amyloidosis, rheumatoid arthritis, ankylosing spondylitis, chronic bronchitis, scleroderma, lupus, polymyositis, appendicitis, inflammatory bowel disease, ulcers, Sjorgen's syndrome, Reiter's syndrome, psoriasis, pelvic inflammatory disease, orbital inflammatory disease, thrombotic disease, and inappropriate allergic responses to environmental stimuli such as poison ivy, pollen, insect stings and certain foods, including atopic dermatitis and contact dermatitis, diabetes insipidus, Type II diabetes, Parkingson's Disease, Alzheimer's Disease, amyloidosis, surfactant protein C deficiency, ABCA3 deficiency, Huntington's Disease, adrenoleukodystrophy, amyotrophic lateral sclerosis, retinitis pigmentosa, polylutamine disease, mad cow disease, alpha one antitrypsin deficiency, short chain acyl CoA dehydrogenase deficiency, inclusion body myositis, and the aging process. The inflammation characteristic of many of the above inflammatory diseases (or those having an inflammatory component) can be linked to the aforementioned NFκB-mediated chronic inflammatory response pathway.
Although there has been notable progress in understanding the basis of inflammatory diseases, many of the therapies for controlling inflammatory diseases and disorders, and especially for treating cystic fibrosis, possess obstacles and disadvantages. Accordingly, therapies for treating cystic fibrosis and other diseases and disorders having a NFκB-mediated chronic inflammatory response component are needed.
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.